首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   69篇
  免费   5篇
  国内免费   5篇
电工技术   4篇
化学工业   22篇
金属工艺   5篇
机械仪表   5篇
建筑科学   1篇
能源动力   3篇
轻工业   26篇
水利工程   1篇
一般工业技术   10篇
原子能技术   1篇
自动化技术   1篇
  2021年   2篇
  2018年   1篇
  2017年   4篇
  2016年   1篇
  2014年   1篇
  2013年   6篇
  2012年   1篇
  2010年   2篇
  2008年   2篇
  2007年   1篇
  2005年   2篇
  2004年   3篇
  2003年   5篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   2篇
  1997年   7篇
  1995年   2篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1988年   2篇
  1986年   1篇
  1985年   4篇
  1984年   3篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1971年   2篇
  1970年   1篇
  1967年   1篇
  1964年   1篇
  1960年   1篇
  1954年   1篇
排序方式: 共有79条查询结果,搜索用时 15 毫秒
41.
Microbial load and viscosity of brown rice, rough rice, wheat and buckwheat exposed to electrons at different acceleration voltages were examined and compared with those irradiated with gamma-rays. Electrons at acceleration voltages of 180–225 kV reduced microbial loads of grains to <100 CFU/g. The viscosities of aqueous suspensions of grains treated with such low-energy electrons were almost the same or higher than those irradiated with gamma-rays at 0.1 kGy, much lower than necessary to disinfect grains. Results suggest that low-energy electrons can decontaminate grains with little starch degradation compared to gamma-rays.  相似文献   
42.
Distorted tetragonal YNbO4 crystallizes from an amorphous material prepared by the simultaneous hydrolysis of yttrium and niobium alkoxides. It can be preserved at room temperature by quenching and has a unit cell with α=0.5164 nm and c= I,0864 nm. The structure contains tetrahedral NbO4 groups.  相似文献   
43.
Thermoluminescence dating has attracted the attention of geology and archaeology researchers as a new method. This method requires a heating device to raise the temperature of the specimens at an exact rate. This paper describes the design method of a control system that can achieve this goal. This control system lends to be unstable because of the existence of the parameter perturbation and dead time. In this paper, the perturbation and dead time are treated as perturbations of a nominal plant regarded as a first-order lag time system. Improvement of tracking characteristics in the low-frequency domain and robust stability in the high-frequency domain of the control system are achieved by using the solution of the mixed-sensitivity problem that is a kind of H control theory. Experiments verify the effectiveness of this method.  相似文献   
44.
辽沈Ⅳ型日光温室墙体保温性能试验研究   总被引:3,自引:0,他引:3  
赵岽  王铁良  山口智冶  白义奎 《节能技术》2005,23(5):390-391,429
通过对辽沈Ⅳ型(大跨度)日光温室的北墙相同垂直面不同高度处的实验研究,得出温室的墙体表面温度与室内外温度的关系和热流量及墙体表面蓄放热的变化规律.实验研究表明,温室所采用的墙体具有良好的保温隔热性能.  相似文献   
45.
Determination of Tetrodotoxin by Capillary Isotachophoresis   总被引:3,自引:0,他引:3  
A method is described for the quantification of tetrodotoxin (TTX) in crude extracts of puffer fish by capillary isotachophoresis. Conditions for isotachophoresis consisted of a leading electrolyte of 5 mM potassium acetate, pH 6.0, containing 0.2% Triton X-100 and 0.5 vol of dioxane, and a terminating electrolyte of 10 mM β-alanine adjusted to pH 4.5 with acetic acid. It was possible to quantify the TTX content of crude unfractionated puffer extracts, and obtain values similar to those obtained by mouse bioassays which are time consume.  相似文献   
46.
This paper describes the ordering mechanisms observed in Li ferrite powder samples with different particle sizes and aggregation states, as well as in sintered pellets. Measurement of ordering rates in the powder samples and observation of chemically etched surfaces of partially ordered pellets indicate that the ordering proceeds by a nucleation-growth mechanism and that the ordering initiates at grain boundaries and prevails into the inner part of the grains. In powder samples, surfaces as well as grain boundaries contribute to the initiation of ordering but their temperature dependences are different. The activation energy of the ordering is calculated to be 192 kj/mol.  相似文献   
47.
Two proteolytic enzymes, L.a. protease I and II, were purified from the fruit body of 'shimeji'mushroom, Lyophyllum aggregatum, by ammonium sulfate precipitation, gel filtration, hydrophobic chromatography and ion-exchange chromatography. The enzymes were assayed using t-butyloxycarbonyl-Ala-Ala-Pro-Phe p-nitroanilide as a substrate. Each of the final enzyme preparations was homogeneous on polyacrylamide gel electrophoresis. The molecular weights of the enzymes were estimated as 44,000 and 46,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzymes had the same optimal pH range of 7–8. Protease I preferentially hydrolyzed peptide bonds of the carboxyl-terminal sides of phenylalanine and leucine, and slowly hydrolyzed the peptide bonds of alanine, threonine and asparagine. On the other hand, protease II showed broader substrate specificity. Both enzymes were almost completely inactivated by diisopropyl phosphofluoridate, and partially inhibited by chymostatin. Protease I was also inhibited weakly by o-phenanthroline. These unusual proteases may have potential for specific food treatment applications.  相似文献   
48.
This paper proposes a new high‐efficiency photovoltaic (PV) converter for grid connection through a high‐leg delta transformer, which is composed of a symmetrically connected boost converter and three half‐bridge inverters. One of the three half‐bridge inverters is connected to the boost converter, and the others are directly connected to the PV terminals. This circuit configuration enables to reduce the power losses in both boost converter and inverter. This paper also proposes a new cooperative control method between the symmetrically connected boost converter and inverter. The control method can reduce the average switching frequency to 75% of that in a conventional one, resulting in a great reduction in switching power loss. Experimental results show that the proposed circuit improves its European efficiency from 91.6% to 94.5%.  相似文献   
49.
The purpose of the present study was to investigate the influence of vegetable oligopeptides on the reduction of blood ethanol. Studies were done after intragastric ethanol intake of 1 g/kg body weight ethanol in stroke-prone spontaneously hypertensive rats. Intragastric administered corn peptide caused a significant attenuation of the increase in blood ethanol levels. However, pea peptide did not influence blood ethanol levels. Pea peptide has a similar molecular weight as corn peptide. In the plasma, alanine, branched-chain amino acids, and proline concentrations were significantly elevated by the administrations of all oligopeptides as compared to the control group, but the leucine level was elevated more so by the corn peptide compared to wheat peptide or pea peptide. Consequently, these results suggested that corn peptide may lower the increase in blood ethanol levels after ethanol intake by the marked elevation of plasma alanine and leucine, especially leucine.  相似文献   
50.
A direct solution analysis method, coldspray ionization (CSI) mass spectrometry (MS)[1], a variant of electrospray (ESI) MS operating at low temperature (ca. - 80 ~ 10℃), allows facile and precise characterization of labile organic species, especially those in which non-covalent bonding interactions are prominent. We have applies this method to investigations of the solution structures of many labile organic species, including unstable reagents and reaction intermediates, asymmetric catalysts, supramolecules, and even primary biomolecules.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号